Conventionally, when a gasoline engine vehicle is fueled with gasoline, which is an energy source, the user, holding a fueling lever, can feel sound and vibration caused by gasoline flowing and know fueling is ongoing, and can recognize also from rotation of an indicator and sound from a pump that fueling is ongoing. Since the power of the vehicle is off during fueling, the amount of gasoline supplied is not indicated by an indicator on the vehicle. However, the user can recognize by the fuel pump stopping supplying gasoline that the gasoline tank has got filled up.
On the other hand, for electric vehicles, such as EV/PHEV vehicles, when the battery is charged, which is an energy source, charging starts when a charging connector provided to a power supply outside the vehicle (hereinafter referred to as an external power supply) is set into a charging port provided on the electric vehicle. If there is any display on the charging supply side, or if there are segments for charging or the like on an indicator on the vehicle, the user can recognize that charging is ongoing. Then, with a lamp indicating power-feeding on the charging supply side turning off, or an indication by the segments of an indicator on the instrument panel, the user can recognize that the battery has been fully charged.
Meanwhile, conventionally, in order to supply AC power for household use utilizing the equipment (such as a battery) on a vehicle when a power outage occurs, or in case of emergency, or the like, there is a power supply system that includes a power supply apparatus (invertor) which is connected to a battery of a vehicle when a power outage occurs. The power supply system converts DC power, inputted from the battery into the power supply apparatus, into AC power, and supplies the AC power as household use. Among those power supply systems, one with a power supply apparatus (invertor) provided with a display unit that indicates values of current [A] and power [W] has been disclosed (for example, see Patent Document 1 below).
In addition, among high-speed charging apparatuses that rapidly charge a battery adapted to high-speed charging, some high-speed charging apparatuses have a display and setting unit that receives and displays a value of current at every moment during charging (for example, see Patent Document 2 below).